Manufacture of manganese steel.



. isses.

UNITED OFFIQE.

WILLIAM CAMFBELL, or NEW roux, u. 1., JOHN H. nnnn or HIGH BLR-IDGE fiQEW JERSEY, Jinn HENRY M. HOWE, or 1213132501230 sre'rrou, NEW YORK, nssrono iis T0 rnrnon-wnnnrou more AND STEEL COMPANY, n. CORPORATION or NEW JERSEY.

MANUFACTURE OF MANGANESE STEEL.

E0 Drawing.

latenteiil Get. 13, 1914.

To all whom it may concern:

Be it known that We, ILLIAM CAMPBELL, a subjectof His Majesty the King of Englend, and a ICSlt'lQlll] of the city, county, and State of New York, Jouu H. HALL, a citizen of the United States, and a resident of High Bridge, New Jersey, and HENRY M. down, a citizen of the United Statesnend a resident of Bedford Station, Westchester county, -New York, have invented certain new and useful Improvements in the Manufacture of Manganese Steel, of which the following is n full, true, and concise speciheat-ion. I

This invention is on improvement in manganese steel alloys, and provides a new'cless of such alloys possessing the characteristic hardness and toughness of existing forms of manganese steel but contnimn a lower percentsge of manganese, which esture adapts the new product for production at a less costsnot, aiiords practical advantages in certain other respects.

.langonese steel as now made and used contains usually from 11 to i l per cent. manganese, and from 1 to 1.5 per cent. of carbon, ami is characterized not only by its remarkable combination of. hardnes, and toughness or ductility, but also by the peculiarity that it is made malleable by quenching; it, when heated, in a cold liquid. We are adore that it has been hitherto proposed to employ smaller percentages of manganese, but a mnngeuese steel, low in manganese, hes not ye-tbeen produced of commercial or satisfactory character, and we believe it is generally conceded that reduction of the manganese below the above percentage, or say 10 per cent, produces or tends to produce it brittleness in the product akin to the brittleness of glass, which unfits it for practical or commercial use.

Our invention is based on the discovery We have made, that a certain critical relation exists between the percentage of manganese lilll'l the percentage of carbon employed with it in the alloy, and that by proportioning the carbon ingredient in accordance with this relation, e-product steel may be obtained containing comparatively small percentages of manganese, say from 9 per cent. to 6 per cent. or as low 5 per cent. and possessing to a. very valuable degree the characteristic combination of ductility with hardness and the other "well known and ill-j poi-taut properties of the richer alloys. As the percentage of manganese is diminished below about 6 per cent, we obserye that the peculiar properties that ere characteristic of manganese steel begin to disep'peor, as if approaching the region Where innnganese steel. merges into ordinary carbon steel, which, as is known, contains manganese in minute amounts, but of which the properties are quite opposite. There is therefore, as-66 we believe; a practical limit, around 5 per. ccnn, for the diminution of the manganese according to our invention.

The relation We have found to exist between the percentages of manganese and 70 carbon may be expressed by a statement. as follows, of the limits within'whicli the can bon may be usefully present in" steel containing from 9 to 5 per cent, or thereuhout of manganese, viz. an omount equal to .985-.0l of the percentage of manganese us one limit, and an amount equal to .1.25+-gof the percentage of manganese as the other limit, the particular amount of carbon between these limits for any given percentage of manganese being determined according to the degree of ductility desired for the product. Thus, for example, if an 8 per centz manganese steel be required, the mix-hon is Futroducecl in such amounts that the finished product/will cont-sin between (.9s5-.04p 8)=.ce5% and (1.25+ 8)== 1.51694 in percentage of the whole, and if the product be required to be specially (lllC- tile, the amount of carbon present should be nearer the lower of the two limits,the carbon referred to being carbon other than. graphite.

As the carbon content approaches-the By trcmes of its range, as above determined, however, We find an increasing tendency toward brittleness and luck of uniformit in the product, due to an'apparent instability of its molecular arrangement and the disproportionate effects of slight variations in its treatment, and "for this reason we prefer and recommend it somewhatnarrower range wherein the carbon may be introduced in such variable amounts as still to efl'ordsome product, but with practically no danger of control of the character of the resultant be here explained, are believed to exa ate this tendency. In its preferred retrogression of the metal into unserviceable forms.

By Way of explanation, it maybe said a th at 'the-slower the cooling of a casting contaming extreme percentages of carbon, the

greater is the tendency toward retrogression into undesirable brittleness and such brittleness is most apt to occur in thick pieces, the interiorcfwvhich necessarily cools rather slowly. Other causes also, which need not pger- 9 therefore, our product having in its composition an. amount of manganese less than 9 per cent.- and somewhat more than 5 per cent. contains carbon, other than graphite, between or not materially exceeding the folylow'ingnarrower limits, yiz. 1.075-04 of the percentage of manganese as one limit, and 1.075+-- of the percentage of manganese asthe other limit,the percentages being taken with reference to the whole. For example, for an 8 per cent. manganese steel the preferable limits for the carbon are '(1.075-.04 8)=.755% and (1.075 i-- 8)= 1.342%, the particular amount ofcarbon present being controlled Within these limits as before and according to the degree of ductility required in the product..

. The ingredients of the product are preferably measured andbrought together in a "molten state, .as..:is now usual with manerties, the new alloy is characterized-by its ductility and hardness as above stated, and by the fact that it is a poor conductor of v heat, and is practically non-magnetic.

It will, of course, be understcodthat certain other elements may be present in the product in small quantities, as is enerally the case with steel alloys, without epartmg itrom this invention.

. Having described our invention, what we ameters, as a claim and desire to secure by Letters Patent of the United States, is:

1. A manganese steel alloy containing from nine to five per cent. of manganese and containing carbon Within the following limits, viz., substantially 1.075 per cent. minus .04 of the percentage of manganese as one limit and 1.25 per cent. plus Q, of the percentage of manganese as the other limit, and having the qualities of ductility and hardness substantially as described.

2. A manganese steel alloy containing from 9 to 6 per cent. manganese and containing carbon in an amount not exceeding the following limits, viz: 1.075 per cent. minus .04 of the percentage of manganese as one limit, and 1.075 per cent. plus 1, of said per-' centa e of manganese as the other limit.

3. manganese steel alloy containing from 9 to 6 per cent. manganese and having combined therewith an amount of carbon not substantially exceeding the following limits, viz: 1.075 per cent. minus .04 of the.

percentage of manganese as one limit and 1.075 per cent. plus ofsaid percentage of manganese as the other limit, said alloy being practically non-magnetic, and characterized by ductility combined with hardness.

4. A manganese steel alloy containing less than 9 per cent. man anese and containing 0 rbon within the following limits, viz: 1. per cent. minus .04 of the percentage of manganese as one limit, and 1.075 per cent. plus t of the percentage of manganese as the other limit, said alloy being practically nonmagnetic' and presenting the appearance of a homogeneous substance when magnified to 100 diameters and having the characteristic of hardness combined with ductility.

In testimony whereof, we have signed our names to the specification in the presence of two subscribin witnesses.

VILLIAM CAlliPBELL. JOHN H. HALL. 1- I IENRY- M. HOWE) Witnesses as to'W. Campbell:

. A. P. FRAPWELL, R. G. Wnmams. Witnesses as to J. H. Hall:

H. G. KIMBALL, G-.'A. Tmmoa.

Witnesses as-to H. M. Howe:

EDWARD C. Gnonssncx, HELEN M. Tower. 

